The invention relates to a wheel suspension system for vehicles having a wheel carrier supported at a vehicle body or the like by pivotally connected upper and lower wishbone units.
Double-wishbone axles are known which comprise an upper and a lower wishbone which each are pivotally connected with a wheel carrier carrying the wheel at their wheel side end and are pivotally connected with the body at their body side end. A spring is disposed between the pair of wishbones which encloses a hydraulic shock absorber and which elastically supports the lower wishbone with respect to the body. However, such double-wishbone axles have the disadvantage that the longitudinal springing, which is required for the rolling comfort, is difficult to achieve because as a result, during a braking operation, a "wind-up" of the wheel carrier is generated and, in addition, there is considerable twisting of the steering axis.
Furthermore, spring strut type axles are known which comprise a lower wishbone and a spring strut which is pivotally connected with it. In this construction, the steering knuckle, on which the wheel is disposed, is fixedly connected with the lower part of the spring strut. Steering causes the turning of the whole spring strut which on the top and on the bottom is movably connected with the body and with the lower wishbone. A coil spring surrounds the upper part of the spring strut which is combined with a telescopic shock absorber. In the case of such spring strut type axles, high side forces occur at the shock absorber tube which cause increased friction between the sliding parts of the shock absorber strut, increasing the breakaway forces during the compression and the rebound and thus impairing the suspension comfort. Also, in the case of spring strut type axles of this type, the wheel suspension kinematics are coupled with the steering geometry so that an optimization is difficult.
It is an object of the invention to provide a wheel suspension system of the above-mentioned type which has an improved longitudinal springing, less windup of the wheel carrier during braking and permits an optimizing of the steering geometry and of the wheel suspension kinematics.
According to preferred embodiments of the invention, this object is achieved by providing a wheel suspension system wherein a shock absorber tube is connected with its lower end by way of a pivot with the lower wishbone, the upper end of the shock absorber tube supporting itself at the vehicle body or the like, and
wherein the upper wishbone is connected by way of an arm with the shock absorber.
In the case of the wheel suspension system according to the invention, no side forces occur at the shock absorber tube during the normal driving operation, so that the breakaway forces remain low. It is also an advantage that the wheel suspension system according to the invention has a low overall height. The pivotal connection of the upper wishbone on the body side can be carried out in a simple manner because it must support only a small part of a braking torque.
When a lower wishbone is used in the double-pivot construction which has an imaginary steering point, relatively large brake disks may also be implemented.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.